And some communities being sprayed by the county may want to double up with the private program since the county will be spraying with Bacillus thuringeinsis.

Bt was picked as the pesticide of choice for the county's programbecause of lingering questions about the danger that dimilin -- the other major gypsy moth poison -- poses to aquatic life. Dimilin has proven to be up to twice as effective in reducing the damage caused tohardwoods by gypsy moth caterpillars in the county.

"It's complex. There are a lot of factors involved, such as what kind of Bt the county uses and how bad the problem is in each community. There are some new Bts that are almost as effective as dimilin that cost much moremoney. The county may not be able to afford them," Johnston said.

County gypsy moth coordinator Richard Olsen has said that entomologists are still uncertain about whether dimilin really does pose a danger to shellfish.

All aerial spraying programs include Bt buffers around bodies of water.

The county sprays approximately 9,000 acresof hardwood forest every year at a discounted price of about $15 peracre.

The GSPC's private program sprayed 1,000 acres last year ata cost of $30 per acre for dimilin and $40 per acre for Bt. Communities must pay for a minimum of 10 acres to join.

The state also will spray approximately 10,000 acres of the most infested areas with dimilin for free. But very few communities in Severna Park have qualified for the state program this year, Johnston said.

The list of mildly infested communities qualifying for the county program is ready and will be out by the end of the week.

Johnston said he will keephis private program open until the end of the month. By then, each community will know whether it has qualified for the county program and county officials will have decided whether it will use a high-priced, effective Bt or not.

Spraying, to be effective, begins in late April when the gypsy moth caterpillars hatch.

Last year the state reported that the county took "a mild hurricane's" worth of damage from the little pests, with 5,500 acres of oaks losing 60 percent or more of their leaves.

Any tree that loses 60 percent or more of its leaves in two successive years can be expected to die, state foresters say.